Suicide and suicidality is a substantial public health problem among the 16 million college students in the United States: in a given year 9% seriously consider suicide and 1.3% reported having actually attempted suicide (American College Health Association, 2007). While treatment is helpful (Schwartz, 2006), 90% of those college students who commit suicide never sought help within their institution (Gallagher, 2006). Prevention is a logical response, but few broad scale suicide prevention programs targeted specifically toward college students have been tested. Part of the problem is that suicidality is not just the end result of any one disorder it can be an aspect of a wide variety of problems including drug and alcohol abuse (Mean et al., 2005), affective disorders (Moscicki, 2001), anxiety disorders (Sareen, Houlahan, Cox, & Asmundson, 2005), thought disorders (Siris, 2001), problems in social relationships (Helliwell, 2007), and some physical health problems (e.g., Tang & Crane, 2006). There is substantial and growing evidence that experiential avoidance -- the tendency to avoid unwanted emotions and negative thoughts -- is a core common process that contributes to the diverse psychological and behavior problems that lead to suicidality and suicide (e.g., Hayes et al., 1996; Hayes, Strosahl, Wilson, Bissett, Pistorello et al., 2004). Acceptance and mindfulness-oriented interventions have been shown to reduce experiential avoidance and thereby reduce the common psychological problems that are predictive of suicidality (Hayes et al, 2006). This project proposes to evaluate an acceptance and mindfulness-based intervention Acceptance and Commitment Therapy (ACT; Hayes, Strosahl, & Wilson, 1999) -- in a randomized trial in which 720 18 to 20 year old college freshmen are assigned in three annual waves of 240 students each to receive either ACT or a didactic course on adjustment to the psychological challenges of college life. The impact of the intervention will be assessed on: (a) experiential avoidance, (b) a range of psychological, behavioral, health, and academic problems that are known to predict suicidality, and (c) the frequency or severity of suicidality, self-injury, suicide attempts, ER visits, and other risky behaviors. These processes and outcomes will be monitored for two to three years (depending on the wave of intervention). A preventive intervention for college students could be readily disseminated within the higher education structure, suggesting that a successful classroom-based preventative approach could have broad public health implications. PUBLIC HEALTH RELEVANCE: Suicide and suicidality among the nation's 16 million college students is a substantial public health problem (American College Health Association, 2007) that needs to be prevented. Because it is known that experiential avoidance -- the tendency to avoid unwanted emotions and negative thoughts -- is a core common process that contributes to the diverse psychological and behavior problems that lead to suicidality and suicide (Hayes et al., 1996; Hayes et al., 2004), the present project tests the impact of an acceptance and mindfulness-oriented intervention (Hayes et al., 1999) that has been shown to reduce experiential avoidance and thereby reduce the common psychological problems that are predictive of suicidality (Hayes et al, 2006). If successful, a preventive intervention for college students could be readily disseminated within the higher education structure, giving such an approach broad public health implications.